The main objective of processing sugar crops is to extract sugar, and it is important to not only maximize sugar extraction but to also minimize sugar degradation during processing. Post-harvest sugar deterioration is a well-known problem. Mechanical harvesting of sugar crops, annual freezes, and extended storage of crops prior to processing (due to sugar mill shutdowns, long term cut-to-crush times, etc.) may lead to post-harvest sugar crop deterioration due to microbial contamination, which affects both sugar crop growers and sugar mills.
It is also important to maximize mill production efficiency by minimizing downtime and capacity constraints brought about by cleaning operations. Such operations take away from the productivity of the mill and incur costs for cleaning chemicals and labor.
Sugar crop processing, sugar beet processing, and sugar sorghum processing share many of the same equipment, processes, and problems. In short, these processes include the steps of: (i) extracting juice from a plant source by mechanically breaking up the plant structure combined with washing with water or thin recycle juice termed imbibition water; (ii) moving the juice through chemical and mechanical purification to separate solids and impurities; (iii) concentrating the juice in multistage evaporators; and (iv) vacuum boiling the concentrated juice to crystallize the raw sugar. Sugarcane, as will be described below, is but one of several sugar crops known to encounter similar problems and that will also benefit from the invention.
Microbial contamination by way of microorganism invasion in sugarcane stalks occurs primarily through cut ends of the harvested stalks. Once the microorganisms are established in a sugar juice rich region of the sugar cane stalks the microorganisms rapidly proliferate. Leuconostoc and serratia are two of the most devastating bacterial microbes, causing large amounts of post-harvest sucrose losses in sugarcane. As a byproduct of microbial activity, dextran and other polysaccharides are synthesized from sucrose. In addition to the loss of sugar product to these metabolism pathways, the byproducts also cause problems in sugar processing.
Sugar crop deterioration is a well-documented problem. It affects both the cane growers and the sugar mills. Cane deterioration leads to many mechanical and operational problems in sugar mills, including poor clarification, evaporator scaling, decreased crushing rates, increased viscosity of massecuites, crystal elongation, false grain formation, and centrifugation difficulties. Corresponding economic losses are incurred due to yield loss, impurities in the raw sugar product, and increased chemical usage for cleaning of devices used in the production process. Microbial activity utilizes and deteriorates existing sugars to form products such as dextrans, exopolysaccharides, oligosaccharides, organic acids, ethanol, and mannitol.
Currently, microbial activity and the formation of microbial byproducts are managed by the application of biocides, dextranase, amylase, surfactants, viscosity modifiers, and other sanitation chemicals. Drawbacks of these approaches include storage and handling of hazardous chemicals, ineffectiveness of many biocides towards Leuconostoc and Serratia bacteria, high corrosion of equipment from use of chlorine-based biocides, chlorine organic byproduct formation from use of chlorine-based biocides, the high cost of dextranase, the long residence time required for dextranase, and the high cost and downtime incurred by evaporator shutdowns for chemical cleaning. The sugar industry continues to lose millions of dollars annually due to sugar losses from sugar degradation and low-quality sugar due to degradation byproducts. In addition, the industry also spends millions of dollars on enzymes, processing aids, equipment cleaning products, replacement equipment, and employee time lost on equipment maintenance, cleanouts, and repairs.
As a readily available, economical, and versatile oxidizing agent, permanganate (MnO4−1) has played a key role in hundreds of industrial, agricultural, and aqua cultural processes. Permanganate is used for the modification, purification, sanitation, cleaning, bleaching, and deodorizing of commercial products. These commercial products include foods, food additives, and drinking water.
Accordingly, there exists an unmet need in the art for compositions and methods comprising permanganate for the treatment of sugar crops for the reduction of sugar mill production costs and increasing of quality sugar yield.